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Bifunctional single atom electrocatalysts: coordination–performance correlations and reaction pathways


Wan, Wenchao; Triana, Carlos A; Lan, Jinggang; Li, Jingguo; Allen, Christopher S; Zhao, Yonggui; Iannuzzi, Marcella; Patzke, Greta R (2020). Bifunctional single atom electrocatalysts: coordination–performance correlations and reaction pathways. ACS Nano, 14(10):13279-13293.

Abstract

Single atom catalysts (SACs) are ideal model systems in catalysis research. Here we employ SACs to address the fundamental catalytic challenge of generating well-defined active metal centers to elucidate their interactions with coordinating atoms, which define their catalytic performance. We introduce a soft-landing molecular strategy for tailored SACs based on metal phthalocyanines (MPcs, M = Ni, Co, Fe) on graphene oxide (GO) layers to generate well-defined model targets for mechanistic studies. The formation of electronic channels through π-π conjugation with the graphene sheets enhances the MPc-GO performance in both oxygen evolution and reduction reactions (OER and ORR). Density functional theory (DFT) calculations unravel that the outstanding ORR activity of FePc-GO among the series is due to the high affinity of Fe atoms toward O2 species. Operando X-ray absorption spectroscopy and DFT studies demonstrate that the OER performance of the catalysts relates to thermodynamic or kinetic control at low- or high-potential ranges, respectively. We furthermore provide evidence that the participation of ligating N and C atoms around the metal centers provides a wider selection of active OER sites for both NiPc-GO and CoPc-GO. Our strategy promotes the understanding of coordination-activity relationships of high-performance SACs and their optimization for different processes through tailored combinations of metal centers and suitable ligand environments.

Abstract

Single atom catalysts (SACs) are ideal model systems in catalysis research. Here we employ SACs to address the fundamental catalytic challenge of generating well-defined active metal centers to elucidate their interactions with coordinating atoms, which define their catalytic performance. We introduce a soft-landing molecular strategy for tailored SACs based on metal phthalocyanines (MPcs, M = Ni, Co, Fe) on graphene oxide (GO) layers to generate well-defined model targets for mechanistic studies. The formation of electronic channels through π-π conjugation with the graphene sheets enhances the MPc-GO performance in both oxygen evolution and reduction reactions (OER and ORR). Density functional theory (DFT) calculations unravel that the outstanding ORR activity of FePc-GO among the series is due to the high affinity of Fe atoms toward O2 species. Operando X-ray absorption spectroscopy and DFT studies demonstrate that the OER performance of the catalysts relates to thermodynamic or kinetic control at low- or high-potential ranges, respectively. We furthermore provide evidence that the participation of ligating N and C atoms around the metal centers provides a wider selection of active OER sites for both NiPc-GO and CoPc-GO. Our strategy promotes the understanding of coordination-activity relationships of high-performance SACs and their optimization for different processes through tailored combinations of metal centers and suitable ligand environments.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Scopus Subject Areas:Physical Sciences > General Materials Science
Physical Sciences > General Engineering
Physical Sciences > General Physics and Astronomy
Uncontrolled Keywords:General Engineering, General Physics and Astronomy, General Materials Science
Language:English
Date:27 October 2020
Deposited On:16 Dec 2020 16:29
Last Modified:16 Dec 2020 16:53
Publisher:American Chemical Society (ACS)
ISSN:1936-0851
OA Status:Closed
Publisher DOI:https://doi.org/10.1021/acsnano.0c05088
Project Information:
  • : FunderSNSF
  • : Grant IDCRSII2_160801
  • : Project TitlePhotocatalytic Processes at Solvated Interfaces

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